AJAX异步请求

来源：互联网发布：linux c语言创建文件编辑：程序博客网时间：2024/06/02 16:32

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>mytest</title>
<script>
function showCustomer(str)
{
if (str=="")
{
document.getElementById("txtHint").innerHTML="";
return;
}
if (window.XMLHttpRequest)
{

xmlhttp=new XMLHttpRequest();
}
else
{

xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","sow.php?q="+str,true);
xmlhttp.send();
}
</script>
</head>
<body>

<form action="">
<select name="customers" onchange="showCustomer(this.value)">
<option value="">选择一个站点:</option>
<option value="RUNOOB">Runoob</option>
<option value="GOOGLE ">Google</option>
<option value="TAOBAO">Taobao</option>
</select>
</form>
<br>
<div id="txtHint">站点信息显示在这里...</div>

</body>

</html>

//以下是php代码

<?php

$q = isset($_GET['q'])? htmlspecialchars($_GET['q']) : ""//三元运算

//if语句直接做判断；
/*if($q == ""){
echo "";
}elseif ($q == "RUNOOB"){
echo "菜鸟教程
http://www.runoob.com";
}elseif ($q == "GOOGLE"){
echo "Google 搜索
http://www.google.com";
}elseif ($q == "TAOBAO"){
echo "淘宝
http://www.taobao.com";
}
*/

//或switch语句做判断；
switch ($q){
case ""
:echo "";
break;
case "RUNOOB"
:echo "菜鸟教程
http://www.runoob.com";
break;
case "GOOGLE"
:echo "Google 搜索
http://www.google.com";
break;
case "TAOBAO"
:echo "淘宝
http://www.taobao.com";
break;
}
?>

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